Baumstarkite Mineral Data

General Baumstarkite Information

Chemical Formula:

Ag3(Sb,As)2SbS6

Composition:

Molecular Weight = 869.54 gm

Silver 37.22 % Ag

Antimony 38.50 % Sb

Arsenic 2.15 % As

Sulfur 22.13 % S

______

100.00 %

Empirical Formula:

Ag₃Sb_2.75As_0.25S₆

Environment:

Found coating miargyrite. Polymorphic relationship with miargyrite and cuboargyrite

IMA Status:

Approved IMA 2002 (Dana # Added)

Locality:

San Genaro mine, Huancavelica Department, Peru. Link to MinDat.org Location Data.

Name Origin:

Named for Manfred Baumstark(1954-), German mineralogist who first recognized the mineral.

Synonym:

IMA1999-049

Baumstarkite Image

Images:

Baumstarkite

Comments: Fragments of baumstarkite with zoning of darker lamellae with higher As content. (AmMin 87:755).
Location: San Genaro mine, Huancavelica Department, Peru.. Scale: See Image.
© American Mineralogist

Baumstarkite Crystallography

Axial Ratios:

a:b:c =0.9331:1:1.0591

Cell Dimensions:

a = 7.766, b = 8.322, c = 8.814, Z = 2; alpha = 100.62°, beta = 104.03°, gamma = 90.22° V = 543.17 Den(Calc)= 5.32

Crystal System:

Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.798(1)(003), 2.841(0.88)(221,221), 3.158(0.8)(201), 3.425(0.8)(021), 1.3994(0.6)(006), 3.224(0.6)(202), 1.971(0.5)(224), 2.013(0.5)(222), 3.258(0.3)(02<

Forms:

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Forms: ( 0 1 1) ( 0 1 0) ( 1 0 1) ( 2 0 1) ( 1 0 0) ( 0 0 1)

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Physical Properties of Baumstarkite

Cleavage:

{001} Perfect, {100} Good

Color:

Iron black, Grayish black.

Density:

5.33

Diaphaneity:

Opaque

Fracture:

Sectile - Curved shavings or scrapings produced by a knife blade, (e.g. graphite).

Habit:

Inclusions - Generally found as inclusions in other minerals.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

2.5 - Finger Nail

Luster:

Metallic

Streak:

grayish black

Optical Properties of Baumstarkite

Optical Data:

NCalc= 1.36 - from Gladstone-Dale relationship (KC = 0.0672) where Ncalc=Dcalc*KC+1
NCalc= 1.36 - from Gladstone-Dale relationship (KC = 0.0672) where Ncalc=Dmeas*KC+1

RL Anisotrophism:

Strong to weak.

RL Bireflectance:

Weak to moderate.

RL Color:

Gray to white.

RL Pleochroism:

None.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Baumstarkite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	33.15	40.95
420 nm	32.70	40.75
440 nm	32.15	40.20
460 nm	31.60	39.65
480 nm	31.10	39.50
500 nm	30.40	38.80
520 nm	29.95	38.10
540 nm	29.35	37.40
560 nm	28.60	36.80
580 nm	28.10	36.45
600 nm	27.60	35.70
620 nm	27.05	34.65
640 nm	26.45	33.60
660 nm	25.90	32.70
680 nm	25.45	32.40
700 nm	25.15	31.25

**Standardized Intensity (100%) Reflection Spectra of Baumstarkite in Oil**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	19.20	25.95
420 nm	18.40	25.25
440 nm	17.60	24.30
460 nm	17.00	23.80
480 nm	16.40	23.30
500 nm	15.80	22.60
520 nm	15.25	21.80
540 nm	14.70	21.30
560 nm	14.10	20.75
580 nm	13.65	20.50
600 nm	13.20	19.80
620 nm	12.80	18.85
640 nm	12.30	17.90
660 nm	11.95	17.25
680 nm	11.75	16.60
700 nm	11.70	16.30

**Calculated Relative Intensity Colors of Baumstarkite in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	320%
R₁
R₂

**Calculated Relative Intensity Colors of Baumstarkite in Oil**
Relative Intensity	0%	70%	100%	140%	210%	280%	350%	420%	490%	560%	630%	660%
R₁
R₂

Calculated Properties of Baumstarkite

Electron Density:

Bulk Density (Electron Density)=4.72 gm/cc
note: Specific Gravity of Baumstarkite =5.32 gm/cc.

Fermion Index:

Fermion Index = 0.0016594569
Boson Index = 0.9983405431

Photoelectric:

PE_Baumstarkite= 226.23 barns/electron
U=PE_Baumstarkite x rElectron Density=1,067.14 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Baumstarkite is Not Radioactive

Baumstarkite Classification

Dana Class:

03.07.04.02 (03)Sulfides - Sulfosalts

(03.07)where z/y = 2 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals

(03.07.04)Dana Group

03.07.04.01 Aramayoite Ag3Sb2(Sb,Bi)S6 P1 1

03.07.04.02 Baumstarkite! Ag3(Sb,As)2SbS6 P1 1

Strunz Class:

02.HA.25 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.H - Sulfosalts of SnS Archetype

02.HA -With Cu, Ag, Fe (without Pb)

02.HA.25 Aramayoite Ag3Sb2(Sb,Bi)S6 P1 1

02.HA.25 Baumstarkite! Ag3(Sb,As)2SbS6 P1 1

Other Baumstarkite Information

References:

NAME( AmMin, Vol 87, p 735) PHYS. PROP.(AmMin, Vol 87, p 735) OPTIC PROP.(AmMin, Vol 87, p 735)

See Also:

Links to other databases for Baumstarkite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info

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Baumstarkite

Ag3(Sb,As)2SbS6
Dana No: 03.07.04.02 Strunz No: 02.HA.25
Locality:

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